Eu finalmente encontrei um Artigo da AOPA que discute os requisitos para uma torre de controle.
Eles dizem:
The FAA has the authority to establish control towers or discontinue control tower services through the National Airspace System when activity levels and safety considerations merit such action.
Para abrir uma nova torre, deve haver uma relação custo-benefício positiva (o que é uma coisa complicada para calcular). A FAA normalmente paga pelo custo, e aqui estão os critérios que eles listam:
Criteria
According to FAR Part 170.13, the following criteria, along with general facility establishment standards, must be met before an airport can qualify for a control tower:
The airport, whether publicly or privately owned, must be open to and available for use by the public as defined in the Airport and Airway Improvement Act of 1982;
The airport must be part of the National Plan of Integrated Airport Systems;
The airport owners/authorities must have entered into appropriate assurances and covenants to guarantee that the airport will continue in operation for a long enough period to permit the amortization of the control tower investment;
The FAA must be furnished appropriate land without cost for construction of the control tower; and
The airport must meet the benefit-cost ratio criteria specified herein utilizing three consecutive FAA annual counts and projections of future traffic during the expected life of the tower facility. (An FAA annual count is a fiscal year or a calendar year activity summary. Where actual traffic counts are unavailable or not recorded, adequately documented FAA estimates of the scheduled and nonscheduled activity may be used.)
The FARs specifically state that an airport is not guaranteed to receive a control tower, even if the airport meets all the criteria listed above. This is where the contract tower program comes in. The FAA, responding to an airport sponsor's request for an air traffic control tower, can elect to establish a contract tower. The FAA can either elect to pay for the service in its entirety, or enter into a cost-sharing agreement with the sponsor, depending on the results of the benefit-cost analysis. Typically, the airport sponsor is responsible for 10 percent of the cost of construction and operations.
Para o cálculo do custo benefício, eles usam os seguintes critérios:
Site-specific activity forecasts are used to estimate three categories of tower benefits:
- Benefits from prevented collisions between aircraft.
- Benefits from other prevented accidents.
- Benefits from reduced flying time.
Explicit dollar values are assigned to the prevention of fatalities and injuries and time saved.
Tower establishment costs include:
- Annual operating costs: staffing, maintenance, equipment, supplies, and leased services.
- Investment costs: facilities, equipment, and operational start-up.
O artigo contém muito mais informações, juntamente com links para os regulamentos relevantes, etc.